Several authors (Hemingway, Sassoon, Owen) of Remarque's era reflect the mantra of "The Lost Generation." The carnage of the first world war was staggering. Germany lost over 7 million people. In his poem "The Parable of the Old Man and the Young" Wilfred Owen says "half the seed" of Europe was killed.
Even though Remarque was not killed in the war, his narrator was. Both, however, were lost. Paul was literally lost, killed a day before the armistice was signed. Before that, he would admit, he was already lost: directionless. The war signaled the loss of Paul's future, his connection to his friends, family, education, marriage, and profession.
His loss is a kind of existential death: a loss of identity; a loss of a moral epicenter. He feels alienated by the generation before (Kantorek's), and he feels cut off from subsequent generations. So says Enotes editor:
Central to Remarque's novel is the attack on members of Germany's older generation for imposing their false ideals of war on their children. The older generation's notions of a patriotism and their assumptions that war was indeed a valorous pursuit played a crucial role in the conflict. The chief sources of this pro-war ideology were the older men of the nation: professor, publicists, politicians, and even pastors. As the war began, these figures intensified the rhetoric, providing all the right reasons why killing the young men of France and Britain was a worthy endeavor. One Protestant clergyman spoke of the war as "the magnificent preserver and rejuvenator." Government authorities in Germany did everything in their power to try and get the young men to enlist, even granting students special dispensation to complete final exams early so as to be able to join up sooner. As the war broke out, more than a million young men volunteered for service.